1. Field of the Invention
This invention relates to an image forming apparatus using an electrophotographic method and, more particularly, to an image forming apparatus such as a printer, facsimile machine, or photocopier.
2. Description of Related Art
As shown in FIG. 16, conventional color image forming apparatuses 100 using an electrophotographic method frequently use an inline method in which multicolor image carriers 102 are arranged in a row. In FIG. 16, the respective image carriers 102 are formed with electrophotostatic latent images by an exposing means 103, and carry toner images visualized by multicolor toners by means of developing means. A transfer material sent out of a feeding section 104 by a feeding roller 105 receives by transfer the respective color toner images from the image carriers 102 by an electrostatically attracting transfer belt 106, and is delivered to a delivery means 108 provided outside the machine body and stacked there after images are fixed to the transfer material with the application of heat and pressure from a fixing means 107.
Color image forming apparatuses of the inline type used currently, in major part, use LEDs as exposing means as shown in FIG. 17, and such exposing means 103 are structured to be open and closed in a united body with a top lid. The respective exposing means 103 are placed at predetermined positions upon closing the top lid and are immobilized by being pushed by utilizing a compression spring.
However, the image forming apparatus as shown in FIG. 17 is required to move the exposing means together with the top lid when a process cartridge 101 is maintained or replaced or paper jamming recovery is made. Thus, as opening and closing operations of the top lid are repeated, positions of the exposing means correlative to the image carriers are more or less shifted, thereby deviating the exposure positions. This deviation of the exposure positions renders formed images shifted or inclined, and when color images are formed, image defects may occur due to a color shift or like.
To avoid the above problems, a possible structure is that the process cartridge can be removed from an upper portion of the apparatus without moving the exposing means, but this structure is required to dispose the exposing means and the process cartridge in a non-overlapping manner in a horizontal direction in FIG. 17, so that the structure may raise a problem that apparatus may be made larger.
It is an object of the invention to provide an image forming apparatus capable of maintaining and replacing the image carrier units and improving the workability of paper-jamming recovery.
Another object of the invention may become apparent when the following detailed description is read.